Railway signal system



Se z 1925;

pt R. .1. HEWEJT RAILWAY SIGNAL SYSTEM Filed Feb. 19. 1923 -10 Sheets-Sheet 1 :JERI

ATTORNEYS. 3

. -Sept. 22, 1925.

R. ,1. HEWETT RAILWAY SIGNAL SYSTEM Filed Feb. 19. 1925' 10 sn ets sneet s 3 A TORZVEYS.

Sept. 22, 1925 R. J. HE-WETT RAILWAY SIGNAL SYSTEM Filed Feb. 19; 1923 a gdNVENTo R. 7 BY Sept. 22, 1925.

' R. J. HEwETT RAILWAY stems sxsrnu Filed Feb. 19. 1923 10 Sheets-Sheet I Sept. 22, 1925.

' R. J. HEWETT RAILWAY SIGNAL svsmw Filed Feb. 19, 1923 10 Sheets-Sheet 9 A ORNEYSJ Sept. 22, 1925 ,1 1,554,724

R. J. HEWETT RAILWAY smmu. sysrai Filed Feb. 19, 1923 i0 Sheets-Shet 10 AT ORNEYS.

Patented Sept. 22, 192 5, a

UNITED srsr s ROBERT J. HEWETT, 0F WESTFIELD, NEW JERSEY.

RAILWAY SIGNAL SYSTEM.

Application filed February 19, 1923. Serial No. 819,868.

To all whom it may concern:

Be it known that I, ROBERT J, Hnwn'r'r, a citizen of the United States, residing at lVestiield, in the county 01. Union and State of New Jersey, have invented certain new and useful Improvements in Railway Signal Systems, of which the following is a full, clear, and exact description.

This invention relates to railway signal systems with which traffic in both directions over a a stretch of single track between two passing stations may be gm'eined. An objeet or". the invention is to provide an in1- proved signal system with which both absolute and permissive control of traiiic may be obtained in an exceedingly simple, safe and eflicient manner with a minimum of circuits, relays and other parts- A ij'urther object is to provide an improved system with which the presence of a train at any point in a part or all of the stretch of single track may be indicated at one 01'' the passing tracks, and whichmay be employed in connection with signals governing tra'liic in both directions Without the necessity of utilizing additional relays. A further object is to provide an improved signal system which the operation of the switch at the junction of the stretch of single track with one of the passing tracks, for the purpose of connecting the main track with the passing track, will automatically set the signals along the stretch oi single track to govern the movement of a train entering the stretch of single track from the passing track through the operated switch and which will permit a switching movement against opposing traflic. Other objects and advantages will be apparent from the following description of an embodiment of the invention and the novel features will be particularly pointed ont hereinafter in claims.

In the accompanying drawings:

Figures 1 and 2 taken together, illustrate diagrammatically a stretch of single track connecting two passing stations, including the signal controlling circuits with the signals at clear;

Fi ures 3 and 4 taken together, illustrate the same stretch of track with a train about to enter the stretch of single track and with the signals set to permit this movement of the t ain;

Figures 5 and 6 taken together, illustrate the same with the train partly through the stretch of track;

Figures 7 and 8 taken together, illustrate the same with a train at a diiierent point in its travel between the passing stations; and 7 Figures 9 and 10 taken together, illustrate the same with an indicator providing for switching movements against the opposing traflic.

Reference may now be had particularly to Figs. 1 and 2 which taken together illustrate a stretch of single track between two passing stations, in which the control circuits are in normal condition. At the left of Fig. l is shown a typical double or passing track junction in which west bound signal 111 controls west bound traflie over the west bound main track, of which track sec tion T and track relay R form a part. East bound absolute signal 110 controls east bound traffic from the east bound main track to the single track. The east bound main track is connected to the single track by means of the switch S which is normally open as shown. That is, the switch is normally set for a west bound train movement from the single track to the westbound main track of the double track section.

The traclr circuits and track relaysare arranged in the usual way. At east hound absolute signal 110,traclif relay B is connected to track section T At west bound signal 113, track relay R is connected to track section T Each track section T and T is provided with a track battery at their intermediate insulated joints, as shown. Two track sections for each sub-block are shown, One track section only, or any number of track sections may be used.

At the right of Fig. 2 is shown a similar double or passing track junction in which east bound signal 116 controls east bound traffic over the east bound main track, of which t1, k section T and track relay R torin a part. lVcst bound absolute signal 117 controls west bound traflic from the west bound main tract: to the single track. l i' e't bound main trackis connected to the single tracl; by means of the Switch S which is normally open as shown. That is, the switch is normally set for an east bound bound main track section T train movement from the single track to the east bound main track 01 the double track section.

In Figs. 1 and 2 the control circuits and signals are shown in their normal clear condition. In Fig. 1 the control circuit "for east bound absolute signal 110 is as tollo\vs: From line relay L wire 1, contact 2 of track relay R line wire 8, contact 1 of track relay R wire 5, wire 6, absolute contact 7 of east bound line relay L wires 8, 9, positive pole chamber P, positive wires p, 7), battery B negative wire 01, negative pole chamber N and common wire back to the common terminal of line relay L at signal 110. Contact 7 of east bound line relay L provides the through or absolute control for east bound absolute signal 110. The permissive control for east bound absolute signal 110 is provided by back contact 11 of west bound line relay L and is as -follows: From contact 4 of track relay B3 wire 5, wire 10, back contact 11 of west bound line relay L when deenergizcd, wire 12, circuit. controller 13 operated by west bound signal 113 and closed when said signal in its stop position, wire 14:, wire 5), positive pole changer P, positive wires 3), 2), battery B negative wire a, and negative pole changer N to the common wire C.

The control circuit for east bound signal 112 is similar and is as follows:1n Fig. 1 from east bound line relay L wire 1, contact 2 of track relay R line wire 3, in Fig. 2, line wire 3, contact 1 of track relay R wire 5, wire 6, absolute contact 7 of east bound line relay L wires 8, 9, positive pole changer P, positive wires p, 1?, battery B negative wire n, negative pole changer N to common wire C. The permissive control is from contact 4: of track relay R wire wire. 10, back contact. 11, of west bound line relay L wire 12, circuit controller 13 when closed, wire 1%, wire 9, positive pole changer P, positive wires 79, p, battery Pi negative wire a, negative pole changer N to common wire C.

The control circuit for east bound signal 114- is as follows: From east bound line relay L wire 1, contact 2 of track relay R line wire 3, contact 1 of track relay R wire 5, normally closed circuit controller (3 operated by switch S of west bound main track T F, wire 7, positive pole changer P, positive wires 19, 0, battery B negative wire a, negative pole changer ll and common wire C back to east bound line relay L at east bound signal 114. East bound signal 114 being the last intermediate signal in the road block is not controlled by east bound line relay L of east It is, however, controlled by circuit controller 6 of switch S o't west bound main track section T F, the purpose of which is t0 Set the route west bound for a west bound train when about to enter the single track section at signal 117.

The control circuits for the west bound signals are similar and are designated by another set of numerals. The control circuit tor west bound absolute signal 117 is as follower-From line relay L wire 31, contact 32 of track relay R line wire 33,

contact 34; of track relay R wire a wire 36, absolute contact 37 of west bound line r iv L wire 38, 3'3), positive pole changer positive wires 7), p, battery B negative wire 7?, negative pole changer N, and common wire C hack to the common terminal ot west bound line relay L at signal 117. Contact 37 of west bound line relay L provides the through or absolute control tor west bound absolute signal 117. The permissive control for west bound absolute signal 117 is provided by back contact 41 ct east bound line relay L and is as follows: From -contact 34- of track relay R wire 2-35, wi e 410, back contact 11, of east bound line relay L when deenergized, wire 4-52, circuit controller 1-3 operated by cost bound signal 111 and closed when said sgnal is at stop, wire 434:, wire 39, positive pole changer P, positive wires 79, 7), battery B negative wire a, negative pole changer N and common wire G back to line relay L at absolute signal 117.

The control circuit for west bound signal 115 is as follows: In Fig. 2 from west bound line relay L wire 31, contact 32 of track relay R line wire in Fig. 1, line wire 33, contact 3-1., of track relay R wire 35, wire absolute contact 37 of west bound line relay L wires 38, 39, positive pole changer P, positive wires 79, 7), battery B negative wire a, negative pole. changer l? and common wire G back to line relay L at signal 115.

The permissive control for west bound signal 115 is as follows: In Fig. 1 at east bound signal 112, from contact 3% of track relay R wire 35, wire 40, back contact 41. oi east bound line relay L when c sed. wire 42, circuit controller 41:3, closed when signal 112 is at stop, wire 44, wire 39, positive pole changer P, positive wires 79, 7),

battery B negative wire 1?, negative pole changer N and coinn'ion wire (3 back to west bound. line relay L in Fig. 9. The back contact 41 operates as the dominating permissive control and the circuit con troller 43 provides the safety factor for mechanically operated signals which insures proper operation of the signal be'tore the permissive circuit is rendered et ectiveavhere light signal systems are used the mechanically operated circuit controllers for the perm ssive circuit may be omitted.

From the foregoing it is seen that th absolute control is provided by the absolute control contact on each intermediate line .relay in the usual way. The permissive control is provided by the back contact on the companion line relay for the opposite direction and is effective in advance of a train in the running direction. The absolute control and also the permissive control are both provided for by the same line relay. This permissive control by the back contact of the opposite line relay is one of the new and novel features of my invention;

The control oi cuit for west bound signal 113 is as follows: From west bound line relay L wire 31 contact 32 of track relay R line wire 33, contact 34 of track relay R wire 35, circuit controller 36 operated by switch S of east bound main track section T F, wire 37, positive pole changer P, positive wires 10, 3), battery B negative wire a, negative pole changer N, and common wire C back to the common side of west bound line relay L at signal 113. lVest bound signal 113 being the last intermediate signal in the road block is not con trolled by west bound line relay L of west bound main track section T It is, how'- ever, controlled by circuit controller 36 of switch S of east bound main track section '1 F, the purpose of which is to set the route east bound for an east bound train about to enter the single track section.

The line control relays are of the usual neutral-polar type. At east bound absolute signal 110 line relay L is provided with a neutral armature which operates neutral contact 16 also a polarized armature which operates polar contact 20. hen east bound intermediate signal 112 is in either its 45 or its 90 position its pole changer N, P, will be in its normal position as shown and this will supply a current of normal or positive polarity from battery 13 to line wire 3, and east bound line relay L at signal 110 will be energized in .its normal magnetic condition which will hold its neutral contact 16 and also polar contact 20 closed. When east bound signal 112 is in the stop position its pole changer.N, P, will be reversed and this will supply a current of reverse polarity from battery B to l1ne wire 3, and east bound hne relay L at signal 110 will be energized in its reverse magnetic condition which will hold its neutral contact 116 closed and its polar contact 20 will be held open.

I The motor circuits for operating the semaphore signal are of the usual type where neutral polar line relays are used. At absolute signal 110 the 45 motor circuit is from battery B positive wire 19, wire 15, neutral contact 16, wire 17, 45 motor mechanism, not shown, wire 18, negative battery, wire it, to battery B The 90 motor circuit is the same up to neutral contact 16, from Which it is by wire 19, polar contact 20, wire 21, 90 motor mechanism, not shown, and wire 18 and negative wire a to battery B All other motor circuits are the same. lVest bound motor circuits are designated by another set of numerals.

The operation of the system is as follows:*l*igs. 3 and .1 show the circuits set for the east bound train A on the east bound main track approaching absolute signal 110. The switch tender having closed the switch S thecircuit controller 36 is open, and this opens the line control circuit for west bound line relay L at west bound signal 113 which is thereby put to stop. est bound line relay L also opens its absolute contact 37 which opens theline control circuit for west bound line relay L at signal 115 in Fig. 41, which is thereby put to stop. West bound line relay L also opens its absolute contact 37 which opens the line control circuit for west bound line relay L at west bound absolute signal 117 which is thereby put to stop. Setting the switch S has thereby put all west bound signals 113, 115 and 1.17 to their stop position. All east bound signals 110, 112 and 1141 remain clear for the east bound train A.

At west bound signal 1.13 line relay L by closing its back contact 11 closes the permissive control circuit which cuts out absolute contact 7 of east bound line relay L This permissive circuit is as follows: From contact 4 of track relay R wire 5, wire 10, back contact 11 of west bound line relay L wire 12, circuit controller .13, now closed, signal 113 being at stop, wire 14 and wire 9 to the pole changer P, N, for battery B112.

At west bound signal 115 a similar condition of line relay L and signal 1.15 has closed the permissive circuit and out out the absolute contact .7 of east bound line relay= L The absolute control east bound is now out off at line relays L"- and L. The cast bound control circuits now have track relay control only, the same as in ordinary single track signal systems without the absolute permissive feature. This absolute cut off action takes place in advance of the east bound train A.

While the east bound train is passing through track section T track relay R will b deenergized and while passing through track section T track relay hi will be deenergized and this will put absolute signal 110 to stop. While the east bound train is passing through track section T track relay R will be deenergized and while passing through track section T track relay R will be deenergized and this will put east bound signal 112 to stop. hen the eastbound train has cleared out of the foregoing track sections the several track r y as R R R an B Will be again energized in successive order, and east bound line relays L and 11 will be energized. West bound line relays L and L will be deerier :ed and Y-est bound sig; nals 113 and 110 will be at stop. East bound absolute signal 110 will be at 90 and signal 112 will be at 45 as shown in Figs. 5 and (5. i

Fi s. 5 and 6 show the east bound train A in track section T with cast bound signal 112 at 45 and absolute signal 110 t 90. Signal 112 is held at 45 by the closed baclr contact 11 01 west bound line relay L and the closed circuit controller 13 oi west bound signal 115 the complete circuit being as follows: East bound signal 114 being now at stop its pole changer P, N, is in its r verse position, as shown, and battery B supplies a negative current to line wire 3 as tollows:-From common wire C positive pole changer P, positive wires p, 7), battery B negative wire a, negative pole changer N, wire 9, wire 14, circuit controller 13 of west bound signal 115, wire'12. back contact 11 oi west bound line relay L wire 10, wire 5, contact 4 of track relay R line wi e 3, contact 2 of track relay R wire 1, east bound line relay L and common wire C back to the positive pole changer P at signal 114. This negative current will energize east bound line relay L in its reverse magnetic condition which will open its polar contact 20 and prevent the 90 motor circuit from being operated and its neutral contact 16 will hold signal 112 in its 45 position only,'as shown. The 45 position of east bound signal 112 will shift its pole changer P, N, to its normal position, as shown, and this will clear absolute signal 110 to its 90 position. The complete circuit being as follows: From common wire C at signal 112, negative pole changer N, negative wire a, battery B positive wires p, 7), positive pole changer 1 wire 9, wire 8, absolute contact 7, the line relay L being now energized. wire 6, wire 5, contact 4 01 track relay R line wire 3, contact 2 of track relay R wire 1, east bound line relay L and common wire C back to the positive pole changer P at signal 114.

At signal 113 it will be noted that the permissive circuit for signal 110 also is closed as follows:From contact 4 of track relay westbound signal 113, and wires 14 and 9- R wire 5, wire 10, back contact 11 of line relay L wire 12, circuit controller 13 of to the positive pole changer P of signal 112, that is, the control circuit for signal 110 is now held closed by both the absolute contact 7 of line relay L and also by the permissive back contact 11 of west bound control relay L and circuit controller 13 of west bound signal 113. The open condition of circuit controller 36 at switch S holds line relay L deenergized and signal 113 at step. A following east bound train may now be admitted to the block.

The route will be held set for east bound train movei'nents so long as the switch S remains set for admitting an east bound train to the single track section.

In Figs. 7 and 8 it is assumed that no other east bound trains are to be admitted to the singletracl: section and the switch tender has restored switch 3" to its nor mal open position which closes its circuit controller 31', and this clears west bound signals 113 and 115, the control circuits for these two signals being new normal, the same as in Figs. 1 and 2.

The energ Aed condition of west bound line relay L hrow opens its back contact 11 which opens the-permissive control for east bound signal 112. The eastbound train being now in track section T and track relayl-l deenergized, east bound line relayl i also is deenergized and its absolute contact '7 is open. The open condition of absolute contact 7 of east bound line relay L and the open condition of permissive contact 11 of west bound line relay L and the open condition of circuit controller 13 of signal 115 now opens the circuit from battery B to east bound line relay L which will be deenergized and put signal 112 to stop again, as shown.

.In the same way the open condition of absolute contact 7 of east bound line relay L and the open condition of permissive contact 11 0]": west bound line relay L and circuit controller 13 of signal 113 opens the circuit from battery B to east bound line relay L which will be deenergized and put absolutesignal 110 to stop.

From the foregoing it will be seen that in this case the east. bound train being in the stretch of single track, now in track section T when the switch tender restores the switch S to its normal position west bound signals 115 and 113 are put clear and east bound signals 110 and 112 are put to stop. The signals are now in a condition to provide for a back up movement of the train A now in track section T WVest bound signals 11.5 and 113 are clear for the back up west bound movement and east bound signals 110 and 112- are at stop against an east bound movement.

While the east bound train A is in the stretch of single track, restoring the switch S to its normal position puts absolute signal 110 and signal 112 to stop and the block is closed against east bound train movements into the stretch of single track. The switch tender may, however, restore the route to its east bound condition by closing the switch S as before.

East bound signal 116 which is for the double track section is controlled in the ordinary way for double track service and is not involved in any way with the inven tion. The clear position of signal 116 will authorize the east bound train A to pro- 5 ceed' into the double track section T switch S being now normal.

When the east bound tram clears out 01' track section. T track relay R will be energized and track relay R will be deenergized, and hold open the control cir-- cuit for west bound absolute signal 117, and also east bound signal 114 in the usual way. When the east bound train clears out of track section T ti'ackrelay R will be energized and by closing its contact 32 will clear west bound absolute signal 117 and by closing its contact 4 will close the line circuit for east bound line relay L which will be energized by a current of reverse polarity from battery B due to the reverse position of pole changer. P, N, of east bound double track signal 116, it dieing at stop due to the presence of the train intrack section T Signal 114 will be held at its 45 position as usual. This leaves every thing clear in the single track section, exceptsignal 114, the same as shown in Figs. 1 and 2.

Figs. 9 and 10 show a special feature of my invention not found in other single track signal syst-en'is. In Figs. 3 and 4as previously explained, absolute signal 110 being clear, the switch tender has set the switch so as to permit the east bound train A approaching on the east bound main track to enter the single track. This by opening circuit controller 36 has put all west bound signals as 113, 115 and absolute signal 117 to their stop position. East bound signals 110, 112 and 114 remain clear. The stop position of west bound absolute signal 117 closes the block against west bound train movements. In Fig. 10 at west bound absolute signal 117 is shown one of the new features which may be termed a switching movement against opposing traffic. Assume that switch engine l5 now on the west bound main track is to move westward into the single track section T and then eastward into main track section T Switch indicator I is provided for this purpose and is controlled by track sections T T Tu", T and T the control circuit being as follows; From common wire C, indicator I wire 53, contact 54 of track relay R line wire 55, contact 56 of track relay R wire 57, contact 58 of track relay R line wire 59, contact 60 of track relay R wire 61, contact 62 of track relay R wire 63, wires 38 and 39, negative pole changer N, negative wire a, battery B positive wires 7), p, and positive pole changer P to common wire G. Track sections T T T, T and T being now unoccupied, switch indicator I is clear and this authorizes the switch tender to ignore the stop indication oi absolute signal 117 and set. the

switch'S for this special switch engine movement. This movement of the switch 0 Q opens circuit controller 6 which opens the control circuit for east bound linerelay If and this puts east bound signal 114 to its stop position, as shown. The deenergized condition of east bound line relay L by closing its back contact 41 closes the permissive circuit for absolute signal 117 and the negative current from battery B will energize west bound line relay L in its reverse magnetic condition which will open its polar contact 50 and clear absolute signal 117 to its 45 position only as shown. This 45 indication of absolute signal 117 anthorizes the switch engine B to enter track section T and the main track signal 116 being clear, the switch tender will then rei-tore the switch S to its normal position and the switch engine B will then proceed eastward into the east bound main track T and eastward. While this movement is being made the switch engine B Will be in track sections T F or T and the deenergized condition of track relay R b opening its contact 4 will hold east bound line relay L deenergized and its absolute contact 7 for east bound line relay L will be open, but back contact 11 of west bound line relay L being now closed and signal 115 being at stop and its circuit controller 13 closed provides the permissive control for east bound line relay L which being energized by the reverse current from battery B through the reversed pole changer P, N, will hold its polar contact 20 open and hold signal 112 at its 45 position only as shown.

It will now be noted that at signals 115 and 114 both line relays L and L are deenergized. Back contact 11 of west bound line relay L gives the permissive control for east bound signal 112, and back contact 41 of east bound line relay L gives the permissive control for absolute signal 117.

This switching movement changes signal 112 from 90 to its 45 position but does not change absolute signal 110. Theeast bound train A may therefore proceed to signal 112 where it will receive the 45 indication as shown.

In case the east bound train A had already entered track section T deenergized track relay R by opening its contact 62 would hold switch indicator I at stop and the switch tender at absolute signal 117 would not have set the switch S for the switch engine movement.

Only one switch indicator I is shown. The switch S at east bound absolute sig nal 110 should also be provided with a similar switch indicator, as I and control circuit. This has been omitted to simplify the drawings. This switch indicator I is for no other purpose than to permit switching movements against opposing traflic and may be omitted when not needed.

In the foregoing descriptive matter it has been assumed that the main switch as S or S is operated by the switch tender. Obviously it may be operatedby the trainman or by a signalman located at an inter locking station. The double track sections may form part of single track passing sta tions in the same way as may be found in some single track roads in Europe, in Which roads a train arrives at a station on its regular double track section. The invention mayalso be applied to the lap-siding passing track arrangement in single track op eration, in which separate passing tracks are used, one-for each direction. It may also be applied to the third or middle track of a three track road and also to any track of a multiple track road.

I claim: I V

1. In a railway signal system, a stretch of track divided into block sections, signals for said sections, means including a line circuit and a line relay for controlling each signal, each means for controlling a number of the signals being controlled in common by the controlling means of thesignals next in advance that control traliic in both directions therefrom.

2. In a railway signal system, a stretch of track divided into block sections, signals for said sections, and means including a line circuit and a line relay for controlling each signal, the absolute control for each of a number of the line circuits being eii ected by the controlling means for another of the signals, and the permissive control by the controlling means of still another signal.

3. In a railway signal system, a stretch of track divided into block sections, signals for said sections, and means including a line circuit and a line relay 'for controlling each signal, the absolute control for each of anumber of the line circuits being effected by the signal controlling means of the sig nal next in advance that controls trafiic in the same direction, and the permissive control of the same signal by the controlling means of still' another signal in advance that controls traffic in the opposite direction.

it. In a railway signal system, a stretch of track divided into block sections, signals for said sections, means including a line circuit and a line relay for controlling each signal, the absolute control for each of a number of the line circuits being effected by the controlling means for another of the signals, and the permissive control by the con trolling means of still another signal and a circuit controller included in the permissive control operative to complete the permissively controlled line circuit when said still another signal is at danger,and to ,Open it when s aidstill another signal is at clear or caution positions.

Ina railway signal system,'a stretch oi track divided into block sections, signals for controlling traflic through said sections and means including a line circuit and a line relay for controlling each signal, each of a number of the line circuits being branched, one branch constituting the absolute control. and being controlled by the controlling means o't'the signal next in advance and governing traffic in the same direction, the other branch constituting' the permissive control'and being controlled by the controlling means o't another signal governing trafiie in the opposite direction.

In a railway signal system, a stretch of track divided into block sections, signals for controlling itrafl'ic through said sections, in including a line circuit and a line relay torcontrolling each signal, each of a number of the line circuits being branched,

one branch constituting the absolute control and being controlled by the controlling means of the signal next in advance and governing traflic in the same direction, the other branch constituting the permissive control and being controlled by the controlling means of another signal governing tratlic in the opposite direction, and a circuit controller included in the permissive branch of the line circuit and operative with said another signal to complete the permissive circuit when said another signal is set at danger and open the permissive circuit ,vhen said another signal is in all other positions.

I. In a railway signal system, a stretch of traclr, signals arranged along the tracl-t and governing traliic in both directions thereover, means including a line circuit and a line relay'for governing each signal, said means for each intermediate signal. having absolute control of the signal governing means of the signal next to the rear that governs traffic in the same direction,and

having permissive control of the signal governing means of the signal next in advance that governs traffic in the opposite direction.

8. In arailway signal system, a stretch of track, signals arranged along the track and governing tratlic in both directions thereover, means including a line circuit and a line relay for governing each signal, said means for each intermediate signal having absolute control of the signal governing means of the signal next to the rear thatgoverns trafiic in the same direction, and having permissive control of the signal governing means of the signal next in advance that governs tratlic in the opposite direction, said permissive control,including two switches in series, one operable with the signal to closed position when the signal is at danger and open when the signal is in all other positions,

and the other closed when the line relay controlling the relay is deenergized.

9. in a railway signal system, a stretch of track, signals arranged along the track and governing traffic in both directions thereover, and means including a line relay and a line circuit controlling each signal, the line relay of each intermediate signal controlling the line circuit of the signal next in ad vance that governs tratlic in the opposite di. rection and also the line circuit oi the signal next in the rear that governs trailic in the same direction, the line circuits controlled by each relay being opened and losed alternately as the relay is energized or deenergized in the control of its own signal.

10. In a railway signal system, a stretch of track, signals arranged along the track and governing traffic in both directions lZli-ZHQOVGI, .ineans including a line relay and a line circuit controlling each signal, the line relay oi each intermediate signal controlling the line circuit of the signal next in advance that governs traiiic in the oppo site direction and also the line circuit of the signal next in the rear that governs trai'lic in the same direction, the line circuits controlled by each relay being opened and closed alternately as the relay is energized or deenergized in the control of its own signal, and track relays connected at inter vals along the stretch of track and controlling the line circuits oi? the signals, each track relay controlling the line circuit oi? the adjacent signal and the line circuit of the signal next in advance that governs trailic in the opposite direction.

ii. In a railway signal system, a stretch oi track divided into block sections, a pair of signals at each junction of the sections and governing traflic in opposite directions therefrom, and means including a line circuit and a linerelay for governing each signal, the line circuit for each signal being controlled in common by the line relays of the pair of signals at one of the block section junctions next adjacent, one of the common controls of the line circuit being eilective to close the line circuit when the controlling line relay is in one magnetic condition and the other common control being etl'ective to close the circuit when the controlling line relay is in a dili'erent magnetic condition.

in a railway signal system, a stretch of track divided into block sections, a pair of signals at each junction of the sections and governing traiiic in opposite directions therefrom, means including a line circuit and a neutral-polar type ot' line relay ior governing each signal, the line circuit for each nalbeing controlled in COKDIHOII hy the line relays oi' the pair of signals at one of the block section junctions neat adjacent,

one oi the common controls of the line circuit being etlective to close the line circuit when the controlling line relay is in one magnetic condition and the other common contro being etl'ective to close the circuit when the controlling line relay is in a different magnetic condition, and a pole changer in each line circuit and operated by the signal governing traiiic in the same direction and Whose line relay is one 01": those having a control over the line circuit.

13. In a railway signal system, a stretch of track, signals arranged along the track and governing trallic in both directions thereover, means including a normally closed line circuit and a line relay for governing each signal, said means for each intermediate signal when energized having absolute control oi? the signal governing means of the signal neat to the rear that governs traliic inthe same direction, and when deenergized having permissive control of the signal governing means of the signal next in advance that governs trafiic in the opposite direction.

In witness whereof, I hereunto subscribe my signature.

ROBERT J. I-IEWETT. 

